我国回收的南极陨石分类研究综述

OVERVIEW OF CLASSIFICATION OF ANTARCTIC METEORITES, COLLECTED BY 15^(TH) AND 16^(TH) CHINESE ANTARCTIC RESEARCH EXPEDITION IN GROVE MOUNTAINS

到目前为止,我国南极科学考察队共回收到32块陨石样品,其中二辉橄榄岩质火星陨石及钙长辉长无球粒陨石各1块,未分群的铁陨石1块,其余29块均为普通球粒陨石,在普通球粒陨石中有6块是稀少的低铁群非平衡的陨石,表明在回收的陨石中特殊的和稀少的陨石类型占有较高的比例。在综述国外不同南极陨石类型的划分及其频率的基础上,对我国南极和非南极球粒陨石类型进行了初步对比研究,讨论了一些人们所关注的问题,包括陨石富集区、可能发现新的陨石类型、不同球粒陨石群性质与距日心距离的关系及早期太阳星云的连续化学分馏作用等。

Up to date,32 meteorites were collected on the blue ice in Grove Mountains region, Act-arctica, by 15th and 16th teams of Chinese Antarctic Expedition during 1998-1999 and 1999-2000 field seasons. Of the 32 Grove Mountains meteorites, there are 1 Iherzolitic sherg-ottite, 1 eucrite, 1 ungrouped iron meteorite and 29 ordinary chondrites. Six out of the 29 ordinary chondrites are unequilibrated L3 chondrites. Hence, Grove Mountains meteorites are characteristic of unusually high abundance of rare meteorite types. Based on review of classification and the chemical group-petrographic type distribution patterns of meteorites collected in other regions of Antarctica, we conducted a preliminary comparative study of the Grove Mountains meteorites with other Chinese meteorites. Several important issues are discussed in the paper, including meteorite concentrated areas, new meteorite type candidates, relationship between properties of meteorites with their heliocentric distance, and continuous chemical fractionation of early solar nebula.